let arr =[
    {
        shijian: "343530901",
        shijian1: "343540799"
    },
    {
        shijian: "343544400",
        shijian1: "343556820"
    }
    
]

function timeNow(item,parms1){
    let date = new Date(item[parms1]*1000)
    let hours = date.getHours()
    let minutes = date.getMinutes()
    let seconds = date.getSeconds()
    let nowYear = new Date().getFullYear()
    let nowMonth = new Date().getMonth()+1;
    let nowDay = new Date().getDate()
    let nowDate = `${nowYear}-${nowMonth}-${nowDay}:${hours}:${minutes}:${seconds}`
    let StartTimes = new Date(nowDate).getTime()
    item[parms1] = StartTimes
}
for(let i = 0,l=arr.length;i<l;i++){
    timeNow(arr[i],'shijian')
    timeNow(arr[i],'shijian1')
}
console.log(arr)